I think it could be done, maybe with a Turbax1 and a .46. However, there would be alot of effort involved and many opportunities to make the thing way too heavy to fly or to leave it way too weak. If you are a scratch builder, you could consider it a 3-d plan to use as a start, but nowhere near a finished airplane. You'd need to consider structure, access panels, ducting, to name a few. Get one wrong and you've got a lemon.

I've allways thought the CBM would be a good starting point to "scratch" build an F-16 XL.